1. Field of the Invention
The present invention relates to a photosensitive conductive paste for transferring that is applied onto a surface of a transfer support of a photosensitive transfer sheet to be used for forming a conductive layer in a predetermined pattern, and a photosensitive transfer sheet formed by using the same.
2. Description of Related Art
It is known a photosensitive conductive paste for transferring applied onto a surface of a transfer support, the paste including metal powder, inorganic material powder and photosensitive resin, for instance, disclosed in JP 2001-264965. That kind of the photosensitive conductive paste for transferring is used for forming, for instance, a conductive layer of a laminated chip element such as a chip type laminated ceramic capacitor and laminated inductor. It is manufactured by applying the paste onto a surface of the transfer support and drying, exposing and developing it to have a predetermined pattern, and transferring it on a ceramic sheet, and by repeating the steps to form the laminated layers and burning.
It is a disadvantage that the aforementioned photosensitive conductive paste for transferring that includes photosensitive resin for photosensitivity, has more resin than the conductive paste for printing that is burnt after printing has, and accordingly, it is difficult to obtain the required electric capacitance due to reduction in the density of the conductive layer after dried or burnt. However, reduction in the content of the amount of the photosensitive resin for the required density of the conductive layer, causes difficulty in exposing and developing and deficiency in precision of the pattern due to generation of the residue and lack of a sharp pattern. Especially, reduction in the thickness of the applied photosensitive conductive paste for transferring causes more remarkable disadvantage as described above, in order to reduce effects of permeation of the photosensitive conductive paste that increase with the thinner dielectric layer for small-sizing, that is, thinning of the laminated chip element such as the laminated ceramic capacitor and laminated inductor.
It is therefore an object of the present invention to provide a photosensitive conductive paste for transferring to achieve efficiency in exposing and developing and the density of the conductive layer after dried or burnt, and a photosensitive transfer sheet formed by using the same.
The inventors found that efficiency in exposing and developing and the density of the conductive layer after dried or burnt were both achieved by adding any of acrylic resin, rosin-based resin and fluorine-based dispersant into the photosensitive conductive paste for transferring. That is, it was found that acrylic resin, rosin-based resin and fluorine-based dispersant function as a photosensitive resin reduction agent for achieving efficiency in exposing and developing even if the content of the photosensitive resin was reduced.